Married: Elise Stein
Eugene Untermyer was the son of Maurice Untermyer and Sadie Lowenstein, sister of Florence Lowenstein Marshall. Their marriage in 1921 was officiated by Dr. Judah L. Magnes, husband of Beatrice Lowenstein, younger sister of Florence and Sadie. Eugene received his LLB from Columbia University in 1915 and was a lawyer with Guggenheimer, Untermyer and Marshall.
Eugene Untermyer and Elise were divorced after Louise entered Radcliffe and after the family had dropped out of Knollwood in 1944; he subsequently married Marie Antoinette de Bellaigue.
Source: David Marshall Billikopf, personal communication